Invisibility cloak to soon become a reality

Washington, March 14 (ANI): Scientists have created a metamaterial that could lead to the development of a cloaking device that makes a person invisible, among other applications.

Developed by Naomi Halas and graduate student Nikolay Mirin from Rice University, US, the material collects light from any direction and emits it in a single direction, using very tiny, cup-shaped particles called nanocups.

In a research paper in the journal Nano Letters, Halas and Mirin have explained how they isolated nanocups to create light-bending nanoparticles.

In earlier research, Mirin had been trying to make a thin gold film with nano-sized holes when it occurred to him the knocked-out bits were worth investigating.

Previous work on gold nanocups gave researchers a sense of their properties, but until Mirin's revelation, nobody had found a way to lock ensembles of isolated nanocups to preserve their matching orientation.

"The truth is a lot of exciting science actually does fall in your lap by accident," said Halas, Rice's Stanley C. Moore Professor in Electrical and Computer Engineering and professor of chemistry and biomedical engineering.

"The big breakthrough here was being able to lift the nanocups off of a structure and preserve their orientation. Then, we could look specifically at the properties of these oriented nanostructures," Halas added.

Mirin's solution involved thin layers of gold deposited from various angles onto polystyrene or latex nanoparticles that had been distributed randomly on a glass substrate.

The cups that formed around the particles - and the dielectric particles themselves - were locked into an elastomer and lifted off of the substrate.

"You end up with this transparent thing with structures all oriented the same way," said Mirin.

Halas and Mirin found their new material particularly adept at capturing light from any direction and focusing it in a single direction.

Redirecting scattered light means none of it bounces off the metamaterial back into the eye of an observer. That essentially makes the material invisible.

"Ideally, one should see exactly what is behind an object," said Mirin.

"The material should not only retransmit the color and brightness of what is behind, like squid or chameleons do, but also bend the light around, preserving the original phase information of the signal," he added.

Apart from invisibility cloaks, the metamaterial could also light the way towards high-powered optics and ultra-efficient solar cells. (ANI)